Convert a 3d model into a simple 2d model
One way of doing this:


Set up your scene with an orthographic camera facing the model you want to "flatten".
In the User Preferences, under Add-ons, search for svg and enable Render: Freestyle SVG Exporter and Import-Export: Scalable Vector Graphics (SVG) 1.1 format.
Under the Render properties panel, check to enable Freestyle and Freestyle SVG Export, and under Output set the path to somewhere intuitive (I used the desktop).
In the Render Layers panel, under Freestlye Line Set, uncheck the "Edge Types" Sillhouette, Border, and Crease, and check only the edge type External Contour.
Render the image and an SVG will be placed on your desktop. Under File > Import select Scalable Vector Graphics and select the file on your desktop.
At the center of your scene, the flat monkey head is imported as curves. To clean up the imported svg, I took these measures:


Select all of the curves and use Ctrl + J to join.
Convert to mesh with Alt + C.
In Edit Mode, select all vertices and remove doubles.
Select all vertices and make an N-gon Face between them with F. (Not a clean solution, but should work for most 2D-object purposes.)
In object mode, set geometry to origin with Shift + Ctrl + Alt + C



Now you have a flat model of your mesh, with only the minimal amount of vertices and no extraneous faces or geometry.